Principles of Tree Improvement Basic Ideas of Tree Improvement: Tree improvement Tree genetics (Forest genetics) variation in flowers (Hunsoor Teak, Kiravatti Teak) Tree Breeding Applied science Tree Improvement Improving the characters Deals with improving yield using genetics and breeding. Tree Genetics Deals with genetics study of forest tree such as understanding genetic control of character, assessment of variation with respect to character, determining genetic diversity of a population, understanding genetic and evolutionary relationship among different species of trees. It is essentially a kind of basic science. Forest Tree Breeding Refers to activities that are geared to solve specific problem and to produce a desirable end product. Eg. Developing lines with specific wood quality etc. It is essential an applied science. Forest Tree Improvement Is a combination of all tree breeding skills with forest management skills. It is a hybrid science where forest management is clubbed with controlling tree parentage. Basic Objectives or overall goals Production of desired quality product in maximum amount in the shortest period of time at a reasonable cost. Camptothecin active ingredient in Acuminata(0.03) Mappia is rich source(1%) but in China Camptotheca Steps in Tree improvement programme 1. Determination of the species or geographic source within a species that should be used in a given area. 2. A determination of amount, kind and cause of variability within a species. 3. Packaging of desired qualities into improved individuals such as to develop trees with combinations of desired characteristics 4. Mass producing improved individuals for reforestation or commercial purposes. 5. Developing and maintaining a genetic base population broad enough for the needs of advanced generation.

Step 1: The problem of which species to start with is unique to tree improvement because most of the forest tree species are not genetically improved. Sustained commercial importance of a species, sustained product profile of a species and future projection of the same need to be consider before selecting a species for genetic improvement since, genetic improvement activities may take long number of years. Which geographic source Malaria -----drug cinchona Cinchona rergeriana Bolivia PeruPeruvian bark While developing varieties for different agroclimatic zones use of right kind of geographic source is very important. The source from which planting material was developed should be match with the target area where commercial planting can be taken up. Variation in tree species are influenced by both genetic aspects and environmental factors. Assessing quantitatively the amount of genetic and environment component of variation is an important step. Much of the techniques in tree improvement address these issues. In tree improvement programmes using hybridization and vegetative propagation of the hybrid has been successful in few species. Through artificial hybridization has several advantages it is a difficult proposition in tropical broad leaved species such as teak. For this reason a tree breeders major it for commercial plantation. Vegetative propagation or tissue culture provides quick and large genetic gain and are employed for mass multiplication. In species where tissue culture is not possible development of seed orchard, development of seed production areas can be used to multiply genetical improved material. Maintenance of large genetic base and conserving genes in breeding programmes is an important step. This step is missing in many earlier tree improvement programme because of that valuable genetic resources have been lost. Approaches of tree improvement programme 1. Market oriented approach 2. Farmer oriented approach There are two approaches for the genetic improvement of tree species Market oriented approach High input and output situations where genotypes that provide best quality material, fertilizer responsive, irrigation responsive are focused. Farmer oriented approach Genotypes can be developed that will grow satisfactorily on a land which is currently marginal. Strains of trees withstand biotic and abiotic stresses are developed. Phases of a Tree Improvement 1. Research (Developmental) Phase 2. Operational (production) Phase Every successful tree improvement programme has two phases, the first one relates to obtaining an immediate genetic gain by intensively applying principles of genetics to get a desired product.

The second phase consist of improvements for the long term sustenance of genetic gain. 1. Research ( Developmental ) phase Survey and exploration of variation, selection of suitable types, standardization of hybridization, building broad genetic phase etc. are taken up. The major objective of this phase to combining the desired characteristics into one line and to retain broad genetic phase. 2. The operational phase focuses on production of improved material in a shortest period of time and the distribution to the public. Advantages of Tree Improvement 1. One major advantage of genetic improvement of forest tree is that once change is obtained it can be kept over a number of generations. As against this, if an improvement is made through silviculture they will have to be done every rotation. This quality of permanence of genetic improvement reduces recurring cost of tree production. 2. Most of the forest stands show a great amount of genetic variability which needs to be identified, isolated and multiplied for operation level planting. 3. Genetic improved material develop through selection can be kept intact for indefinite time period through the methods of vegetative propogation. Limitations of Tree Improvement 1. Difficulties associated with longevity of the tree 2. Size- which creates problem in measurement, management, seed collection and crossing etc. 3. Slow generation time- Poor juvenile to adult association specialy for growth characteristics. 4. Availability of seed with known or desired genetic background is frequent problem 5. Lack of knowledge about biology of tree species is often a big problem. 6. Another major problem is permanence of organization and movements of research personnel. When did the tree improvement started? MesopotamiaDate palm (Dioceous) First civilization Controlled pollination to maintain parentage. Coorge mandeling orange ( now maintained by IIHR) 1. The cartiest evidence for controlling parentage in tree species is depicted in bas-relief in the palace of Nimrod on the east bank of Tigri river (current day Iraq) this relief portrays the act of a winged god pollinating the date palm with a specially selected male tree. The belief is that it increases the yield and improves the quality of date palm. In this religious practice selection of a male parent and controlling the parentage of the offspring can be seen. Chanakya, the prime minister of Chandragupta Maurya, has mentioned in his Arthashastra that 18 variation of sandal wood categorized based on aroma and colour of wood. This is perhaps first record of geographi variation or provenance variation in a tree species.

Chronology of Tree Improvement (Tree Genetics) : Year 1717 1761 1840 1905 1909 1918 1930 1935 1976 Scientist Bradley Koehreuter De-Vilmorin Dengler Johanssen Sylven Larsen Nilson-Ehle Hyun Country England Germany France Germany Sweden Sweden Denmark ----------Korea Contribution Importance of seed origin in trees First plant hybridization Hybrids in Fir Provenance test for Fir Recognized Elite Stands Seed orchard Controlled pollination in Larch Triploid Aspen Interspecific hybrid of Pine Kedarnath Teak Improvement Kyushu Terminology used in Tree Improvement : Progeny: Tree produced from seed of a tree is called its progeny. Family Individuals that are more closely related to each other to other individuals in a population. Generally this term is applied to denote individuals who have one or more parent common Half sib family Full sib family Sibblings : A group of individuals within a family are called siblings. The group related siblings with only one parent common is called half sib family. A group of related individuals when both the parents are common are called full sib family. Open pollinated family: When siblings are raised from seeds of a cross pollinated trees the family is called as open pollinated family. Theoretically it is a mixture of both full sib and half sib. How ever for all practical purposes open pollinated family is considered as half sib family. Population: The term population is loosely used in tree improvement to designate a group of interbreeding individuals of a species. Vegetative Propagation:

1. To maintain genotype/ uniformity 2. Faster growth 3. Early flowering Uses of vegetative Propagation 1. General uses in forestry 1. Preservation of genotypes through the use of clone banks 2. Multiplication of desired genotypes for special uses such as seed orchards or breeding orchards. 3. Evaluation of genotypes and their interaction with the environment through clonal testing. 4. Capture of maximum genetic gain in operational planting programmes. 5. Accelerating reproduction cycle for faster breeding and testing. 6. Development of *Arboreta for scientific studies. 7. Use of vegetative *propagules for operational planting. The donor tree or mother tree from which vegetative propugules have been taken is called ortet. Individuals propugules derived from an ortet are called ramet. A group of ramets derived from one donor tree (ortet) is called a clone. Hence only clone can be derived from one ortet. In tree improvement tree stand is synonymously used to designate a population. 6. Race Groups of populations that generally interbreed with one another and that intergrades more or less continuously are called races

Many kinds of races are recognized a) Elevational races b) Geographic racessynonymously used as Provenance. c) Edaphic races d) Climatic races 7. Native Vs Exotic Grenet- Seed originated plant or propagule originated from a seed. An exotic spp is the one which is grown out of its natural geographic range. Ex. Himalayan Chirpine grown in Karnataka is exotic. Defining a native species is difficult because of connotation to political boundary. Ex. Chirpine is native to India but exotic to Karnataka. A species growing well within its historical natural range is native species. 8. Item a. No. of characteristics considered to explain b. Pattern of variation c. Cause of variation d. Uses Cline One trait at a time Continuous Mostly environmental Mostly used for purpose not for breeding Ecotype Several traits Distinct or Discontinues Mostly genetically based because of natural selection Used as both descriptive and breeding purpose. Variation in natural Stands: Stand Population of tree species Cohart= similar age trees Forester are exceptionally fortunate to work with a pool of high natural variability. If the selection in natural stands to be successful it is necessary to identify and quantify variations due to 1. Age ( Developmental cause) 2. Genetic make up 3. Environmental causes. From the view point of tree improvement variation due to genetic causes are very important. Unfortunately there is no simple method of estimating variations due to genetic and environmental causes. Experience over years has suggested that first a determination of amount and kind of variability should be done correctly. For this a sampling method called Nested sampling method should be used. A nested sampling method/procedure involve determination of

variability i.e. due to province effect, site effect, due to stand and ultimate to individual trees hence it is necessary to understand the nature of variation in the following levels. 1. Geographic variation ( Provinance variation) 2. Variation between sites within a provenance 3. Variation between stands within site 4. Variation among individuals within a stand 5. Variation within individuals. The study of natural variation of a given species should start with the determination of geographic differences (Provinance variation) and then variation might be present in lesser categories. Knowledge of where the bulk of variation present will help in the developmental of specific traits. It is necessary to understand features associated with different levels of variation and their utility in tree improvement. 1. Geographic Variation Genetically controlled differences are often large, specially for adoptability traits. Knowledge and use of geographic variation within species is key for success of tree improvement. 2. Variation between(among) sites within a provinance Most of the variations are not genetically fix and only represent the effect of varied environment. Not very useful for tree improvement programme. Ex. Bole characteristics of tree species in a coastal site will be crooked and bent due to constant wind action/pressure. Although the progenies may show clear and straight bole when grown inland. 3. Variation between stands within a site. The genetic differences are usually, small usually stand to stand differences are small even though they are genetically controlled and hence can be conveniently ignored. Stand to stand variation is also contributed by past history of logging 4. Variation among individuals within a stand. This is one of important level of variation because plus tree identification in a natural stand has shown that individual tree difference with respect to quality traits and resistance traits are largely genetically controlled. In general, most economic characters show variation between individuals and hence it has special value in tree improvement. An exception among forest tree species which does not show large variation between individuals is Pinus resinosa (red pine) 5. Variation within a tree occurs for few characteristics such as leaf size, wood quality, fruit set, parent etc. This is an important level from the viewpoint of sampling Within tree variation is important because it influences the types of measurement and position of sampling for sound comparison of individuals. Provenance Site Stands individuals Within individuals Wood specific gravity(%) 15 5 0 70 10 Cold tolerance (%) 70 0 0 30 --

In general provenance variation and tree to tree variation accounts for bulk of genetic variation found in natural stand. As shown by Zobel in pine variation for wood specific gravity which is an economically important trait 70% total variation is found among individuals. While most of variation for cold tolerance which is an adoptive trait is found between provenances. Hence while sampling for maximizing genetic variation appropriate corrections could be made to sample either more provenance or more individuals within a stand based on characteristic of interest. Variation in pedigree Stand: Half sib families or full sib families when grown as tree stand known as pedigree stand. Since the genetic relatedness among family is known, we can estimate genetic parameters of particular trait. Hence phenotypic variation can be divided into genetic and environmental components only when pedigree stands are available. For a long term tree improvement programme it is essential that pedigree stands are developed and maintained. MUTATION Gene flow fragmentation Mutation Tree stand Natural selection Forces that increase variation F Gene base Forces that narrows down genetic variation Gene flow Genetic Drift All variations in natural stand has occurred because of natural forces. It is important to recognize forces that increase or decrease the genetic base of a population to understand and mange natural variation. The above schematic diagram represents four forces that influence the genetic base of population 1. Mutations are ultimate source of variation for any natural variation. They are sudden heritable change in an organism at the level of gene. Today mutations are deleterious to the organism. The range of variation that we see an organism is a result of fixation of useful mutation in the population. 2. Gene flow (Gene migration) Migration of genes or alleles from one population to another population can occur through natural process of cross pollination or through seed dispersal. In certain cases gene flow can occur between two species through the process of introgression introgression leads to inter specific hybridization. We can utilize the concept of gene flow in tree improvement.

Ex. Pinus jefferii and P.coulteri are two major species of pine. Jefferii is silviculturally better performing and susceptible to *pine weevil where as coulteri is resistance to pine weevil because of thick bark but has poor performance. An inter specific hybrid has been created which has been backcrossed with jefferii to create a new line with weevil resistance. 3. Natural selection It is a strong natural force which reduces genetic variation, because it is directional (selection of best fit) but it is a slow process and often difficult to measure in short time period. 4. Genetic drift Is a complex mechanism that operates through chance fluctuations as a result of natural calamities and leads to unpredictable changes in gene frequencies. It is non directional and can lead to severe loss of genetic variation. In addition to the natural forces many changes in genetic variation can be brought about by human beings. Dysgenic selection is defined as a process of selection (human beings) where best genotypes are removed (killed) and poor once are left for reproduction. This process ultimately skews the gene frequencies to cause loss of best alleles. No matter how sophisticated breeding methods, the largest, the cheapest and the fastest gains in TIP are obtained by the use of right kind of seed source -Zobel 1980 Provenance: Denote the original geographic area from which seeds or other propagule are obtained. Seed source is the immediate source from which seeds or other propagules are collected. However they need not be original native origin. Some scientist use these terms synonymously. Identifying , delineating the provenance variation to match the breeding objectives is an important area of research in tree improvement programmes. A reliable provinance is the one which produces a descent crop with 90% probability rather than producing an outstanding crop only 50% of the times *Geographic race is a sub division of species consisting of genetically similar individuals and they are related by common descent and occupying a particular territory to which it is became adopted by natural selection. *Racial Development it is important to recognize the conditions in which racial developments takes place rapidly, because such areas can be focused for sampling fine scale sampling for genetic variations. 1. Species growing in wide altitudinal range generally develop more races. Eucalyptus species in Australia show higher racial difference than the plains of Brazil. 2. Species that are growing in diverse soil, soil moisture, and aspect. 3. Species that are growing in diverse environment over a large latitudinal range. Land Race Is a population of introduced individuals that has become adopted specific environment in which it has been planted. In other words, a group of best adopted individuals with desirable growth and form of specific land races can also give quicker and large genetic gains in exotic forestry. EXOTIC FORESTRY:

Advantage of exotics in forestry: 1. Exotic species more uniform, easy to handle silvicultural and the products are known and accepted. Every exotic species have a reliable market. As against these tropical hardwood forest specieses are variable, non-uniform, difficult to manage ecologically. The products are not consistent with respect to demand. 2. Exotics have been subjected to genetic improvement, they have short rotation period, high adoptability. ( to moisture stress) As against this tropical hardwood specieses are not very well adopted to drier regions, if adopted they are very slow growers. 3. Exotics are suited for intensive management and plantation culture, many indigenous species cannot be grown on plantation scale because of a. Non- availability of seeds b. Unknown seed biology c. Unknown parentage 4. Wood quality of many of the exotics is very well understood and suitable for industrial applications. Many of tropical hardwood species have not at been worked for industrial purpose. Problems of exotic forestry 1. Immediate failure of plantation of introduced species. 2. Delayed failure which is a common problem among exotics for following reasons. a. There is good survival and growth in initial years but plantation develops into useful forest. This often occurs because of planting a high latitude species or high altitude species in lower regions. b. There is a good survival and growth of introduced species but the wood is not suitable for purpose to which was planted. c. Exotics show good initial survival and growth but there is a delayed by a pest. i. A previously unknown pest/disease may affect plantation ii. A known pest of native region of exotic may become important in introduced plantation. iii. Previously uneconomical pest may become an important economic pest/ disease. 3. The major problem of exotics is continued substandard performance finally the growth of introduced species may be hindered due to a shortage and absence of a suitable mycorhiza. This has been major problem can be overcome by the use of habitat soil in the growing media. Broad generalization for Exotic Introduction. 1. Do not move the species/ provenances from Mediterranean climate to continental climate. It is some what safer to move sources from continental to near coastal regions. 2. Do not move provenances/ species from areas of uniform climate with small fluctuation with respect to rainfall and temperature, to those areas with severe and large fluctuations.

3. Do not move provenances/ species from higher elevation or high latitude to areas of lower elevations or lower latitudes and vice-versa. Sometimes sources of higher elevations in lower latitude can be moved to areas of lower elevation of higher altitudes and vice versa. LATITUDE HIGH LOW HIGH NILGIRI LOW NORTH INDIA 4. Do not plant provenances/species originating from basic soil on to acidic soil and vice versa. This rule also holds good for sand to clayey and clayey to sand condition. 5. It is safe to move a provenance up to elevation of 300m or 160 km latitude. Selection methods 1. Mass Selection or individual selection. Unit of Selection Individual Criteria Performance (phenotype) of that individual. Mass selection involves choosing individuals based on their phenotypic characteristics (without regarding any information on performance of sibs or relatives). This is the most often a staring point for tree improvement of wild species. This can be practiced in both natural forest and plantations. However mass selection is rarely followed in those plantations where pedigree is known. This method works very well for those characteristics which have high heritability. 2. Selection through progeny testing. Progeny testing involve selection of parent trees based up on the performance of their progeny. This is precise method of selection. This is also a ultimate way of selecting an individual selection for low heritable characters can also be made very effective. This method allows direct estimation of breeding values of individuals. However this is not a very popular method of selection in initial period of tree improvement programme. It takes a lot of time for evaluating progenies. 3. Sib selection. Is a form selection in which individuals are chosen based on the performance of their sibling and not based on their own performance. In situations where destructive harvesting is must for measuring an economic trait (such as heartwood oil content) this sib

selection is adopted. However this method of selection is used in forestry because of destructive sampling. Here the unit of selection is part of the family criteria for selection is performance of sib. 4. Family selection Involves choise of entire family on the basis of their phenotypic mean. There is no selection of individuals within a family. This method is adopted only when we have either half sib or full sib family structures. Family selection is itself is not used in forestry because of increased inbreeding due to rejection of entire families. Family selection best even for low heritable traits because we are considering average performance which minimizes environmental variation. 6. within family selection Here individuals are chosen on the basis of their deviation from family mean and family value percent, family means are not given any weightage. Individuals performing better from poor performing families are selected. This method increases the genetic variability in breeding population and gives slowest rate of inbreeding. 6. Family and within family selection This is two stage selection method which involves firstly, selection of family based on average value followed by selection of individuals based on mean deviation. It consists of choosing best families and best individuals within them. It is predominant method of selection most of the tree improvement programmes. As a refinement of this method combined selection method is used in which an index is completed by giving different weightages to family mean and individuals performance. This works well even for characteristics with low heritability. Selection methods based on number of characters. In most of the improvement programmes several traits are considered simultaneously for improvement however each of these trait may have different importance, may have different heritability. Further when introduced species should adapt well to the new area and survive. Then only improvement of other economic trait can be considered. Based on number of character considered and the sequence of selection. Three methods are as follows . 1. Tandom selection 2. independent culling 3. selection index 1. In tandom selection, breeding for one trait is done at time until a desirable level of improvement is achieved which is followed by breeding for other economically important traits. When exotic species is introduced survival and adoptability is tested and achieved or certain level of pest and disease resistance is achieved which then followed breeding for economically important traits. 2. Minimum standard values are set for every trait and all those individuals which meet this minimum criteria will be selected and others are culled or rejected. Vigour 1 Bole 2 Wood density 4 Pest/disease 3

3. selection index is a kind of multi trait selection system that combines the information on all trees into a index value. This helps the breeds to assign a total score to a individual and rank them. Generally a trait with high economic importance will be given more weightage ( vigour). Those characteristics such as wood density given lower weightage. Apart from the economic weights, heritability of a character is also considered while giving the weights. Construction of selection index itself is an important job which uses multiple regression techniques. In most of the improvement programme selection of trees through selection index is being followed. Selection Methods: Un improved wild plantation Uneven aged stands Even aged stands Objective of a selection propramme is to obtain significant amounts of genetic gain as quickly and as inexpensively as possible while at the same time maintaining a broad genetic base, selection is the key part of all tree improvement programme. The gain obtained from the selection depends on the quality of parent material. A number of selection methods are available to a tree improvement. Based on the pedigree information we have and urgency of selection different methods could be adopted while initiating a tree improvement progamme, selection can be applied in two contrasting situation. 1. Even aged stand/ plantation-raised from seeds of unknown parentage. 2. Un even aged wild stands which are often growing with associated species. There are several advantages in selecting in even aged stands. 1. Breeds can be sured that age will not differ greatly among trees. 2. Relative expression of growth rate, bole form, disease/pest tolerance will not be confounded with the effect of age. 3. Most of the times in a plantation tree are growing under competitive situations which are similar to commercial plantation. 4. By adopting comparison tree method trees considered for selection or graded the best available trees in stand. Which result in highest genetic gain. Candidate Tree A tree that has been considered for grading because of its desirable phenotypic traits but that has not yet been graded or tested. These trees are also called as pre select trees. Plus Trees It is also called as select tree/superior tree. It is a tree that has been recommended for further breeding work for seed orchard etc. following the process of grading and testing. It has superior phenotypic with respect to growth, form, wood quality, resistance etc. at the phenotypic level. However it has not been tested for its genetic worth. Elite Tree Is a term reserved for select trees that have proven to be genetically superior by means of progeny testing. It is ultimate winner in a selection programme. It is most desire kind of tree for mass production of seeds/ vegetative propagules. Selection of an elite tree may take to rotation period.

Comparison/ check Tree While grading a candidate tree many trees are chosen as comparison trees which are locoted in the same stand and are of same age. Candidate trees are compared with these check tree for their superiority. Guidelines For Locating Plus Tree In Even Aged Stand Or Plantation: 1. search for plus trees should be concentrated on plantation that have better growth, straightness and other economic traits which are of interest to breeder. In other words from among different plantations available, selection should 2. Plantation, in which trees are selected, should be located on the same variety of sites where commercial plantations will be established from the improved seed obtained in other words, the stand should match with target sites. 3. When selections are made from plantations, it is better to know seed source from which plantation was established. However, this information is lack for many plantations. 4. Plantation should not be too old or too young compared to economic rotation period. In general should not older than 15 years and younger than 15 years of rotation period. X 15-------- 30 ---------45X 5. Selection should be made only when the stands are pure with respect to species composition. Never select in a mixed species plantation because differential growth rates among species may complicate selection. 6. Never select in a stand/plantation which was earlier logged. 7. Preferably only one tree will be selected in a even aged natural stand. This restriction does not apply to plantation. 8. Always systematic search should be made to eye-ball and to arrive at the best phenotypically good looking tree. 9. Always adopt check tree/ comparison tree method while grading. This helps in minimizing environmental differences and increases the efficiency of selection. Methods For Plus Tree Selection In Un-Even Aged Or Natural Stands: Three methods Y I. Regression system of selection II. Mother tree selection G III. Subjective evaluation/grading i r t h Regression line X Age The most useful method of tree selection in uneven aged natural stand is the regression system. It consists of developing a regression curve for growth with respect to different ages of trees. Using such regression individual trees which show rapid growth is identified and then select it for further breeding. Following are the steps involved.

1. Development of tables relating character of interest and age 2. Development of regression line or graph. Best Girth (cm) 0 Age (years) 100 3. Identifying trees with rapid growth and then selection. To develop a regression line data on an age and growth rate should be obtained from 50 trees from every provenance. Although regression system works well it requires considerable preliminary work of developing regression equation of every major provenance. To complicate the situation age cannot be estimated for all the species specially for those are growing on wet region diffused porous species. II. Mother tree selection When there is no immediate urgency of selection of good trees this method could be adopted. It involves the following protocol. 1. locate phenotypically good trees (about 50) 2. Collect seeds individually from every mother tree and conduct a progeny trail ( with adopting statistical design with good number of replications for at least half a rotation period) 3. based on the performance of progeny mother trees are selected and diploid into seed orchard. The product of mother tree selection is an elite tree Limitation 1. Time required for mother tree selection is very long III. Subjective grading system Some persons who are very familiar with specific species can judge and grade individual trees which are phenotypically better without a comparison or check tree method. Based on expertise of the grades subjective grading method results in moderately good genetic gains. In the absence of pludged tree improvement programme, this method can be adopted to get quick gains.

Simple Recurrent Selection: Step I Natural stand X X X X X X X X X X X X Generation 0 New base O O O O O O O O O O O O Generation 1 As suggested in recurrent selection many cycles of selection and interbreeding among selected individuals is followed. Recurrent selection is followed in those species which have less rotation period, easy to make artificial cross pollination, those industrial important and for those characteristic which have low heritability. Steps 1. Selection of superior phenotype from natural stand or plantation 2. collection of seeds from selected individuals and establishing new breeding population called generation o 3. Again select superior phenotype from generation o and intermate with all selected individuals seeds from such a cross are selected and bulked to create generation 1 4. Repeat selection and intermating among the selected parents to create generation 2. It is called as simple recurrent selection. Reciprocal Recurrent selection; Indirect Selection Ex. Trunk borer. Trait of interest: resistance trunk borer Trait of selection: thick bark

For certain characteristics instead of direct selecting it is easier to select another character which is correlated with it whenever selection is made for a target character based on another trait which is correlated with then such selection is called indirect selection. Ex. Selection of resistance to (target) trunk borer. Based on bark thickness of individual Selection of individual resistance to pest and diseases in Pine based on Terpine content in stem. This approach is specially valuable in those condition when expression of desired character is delayed due to development problem or does not occur because of lack of environment. (pest & diseases occurrence) Condition For Successful Operation of Indirect Selection: 1. There must be a highly co-related character that can be easily measured with the target trait. 2. Heritabilty of target and selected trait should be high. 3. The variability for selected trait should be as good as or better than variability of the target trait. Mass Production of Improved material: The apllied aspect of tree improvement consist of development of improved trees followed by mass production of improved material. No tree improvement programme will be successful in the absence of a proven mass production technique. Every tree improvement programme must have a seed production programme at some stage of their development. If this is not achieved the fruits of tree improvement programme will not reach commercial sector and tree improvement programme will reach at genetic dead-end. The most difficult problem related to the seed production for an operation level programme is to determine amount of seeds needed. The best approach is to plant and produce 30% more seeds than the current requirement. All organizations must give at least 3 year of supply seeds in advance. 1. Meeting the immediate needs a. seeds from superior stand b. seeds from superior provenance or stands c. see production area (SPA) 2. Meeting the long term needs Several methods can be obtained genetically improved seed for commercial sector. In those species which have become commercially important in the near past interim methods have been adopted to get immediate genetic gain. Following three methods can be adopted. a. Seeds from superior individual identified or in the plantations. b. Seeds from good stands or proven provenances. c. Seeds from seed production areas. a. This is available approach for immediate from wild or stand. Mark the tree and collect the seeds from them. Seed collection is done during the logging time. Genetic characters are considered for limb (bole) characteristics. Not > 5-10 trees for acre, 12-25 trees/ha will be suitable for seed collection. b. Seeds from good stands or proven provenance Making mass seed collections only from the best stands (plus stands). If the results of the provenance trail are already available. Large quantity of seeds quickly obtained from proven provenance and can be released as improved material. In many species, seeds obtained from good provenance have given better results.

c. Seed production Areas: SPA: is a stand i.e. generally upgraded and opened by removal of undesirable trees and managed for early and abundant seed production. Seed production areas are also called as seed stands Three important features of SPA: 1. Seeds collected from SPA will have better genetic qualities with respect to adoptability, bole and crown characteristics and pest resistance when compared to seeds from commercial collections. 2. SPAs are reliable sources of well adopted seeds at modest costs. 3. When SPAs are established in natural stand the geographic origins of parent trees is known hence it has a greater value than the commercial collections 4. Very rarely seed production areas are progeny tested Specification for Seed Production Area: 1. The plantation should be nearly full stocked 2. They should be never logged earlier 3. Individual trees must have sufficient crown area so that they can yield large seedcrop 4. The plantation should not be too old or too young. In case of Pine, it should be between 20-30 years. In case of Eucalyptus 45 years, teak 30-40 years. 5. A minimum of 10 acres or 4 ha should be size of stand. 6. generally 50 trees per acre or 125 per hectare are retained (Phonotypicaly superior) 7. For most species an isolation zone or pollen dilution zone should be maintained. Selection of Trees for SPAs: 1. The tree should have high level of vigour, straight good bole formation, free from insect pest and disease attack 2. No tree below the standard will be retained regardless of spacing. 3. The tree should have good crown structure and released for full sunlight. Thinning of SPA: Timing and caution are at most importance when removing undesirable phenotypes from SPA. Timing is important because it determines when the SPA is going to produce the

I-commercial seed crop. Generally it requires at least 3 years for abundant seed production after thinning. Caution should be taken while thinning not to damage the retained individuals at any cost. Management of SPA 1. Removal of logging residues. It is required to minimize the risk of fire hazard and to make SPAs more accessible reduce building up of pest and disease, some times necessary collect the fallen seed crop 2. Spraying of pesticides to reduce the risk of attack on seed crop. (weevils). Timing of spray should be such that it should not interfere with insect pollination. 3. Application of fertilizers to induce heavy flowering and increased fruit set. 4. Development of fire line (10m) 5. Careful removal of canopy to induce lateral growth of branches and expose of flowering branches to the sunlight. Harvesting of seeds from SPAs Among SPAs some are considered as semi permanent when an SPA is established before the economic felling of the plantation, under such circumstances harvesting is done along with a logging. Permanent SPAs are those which are managed year after year for seed production. In these permanent SPAs harvesting should be done carefully not to affect the future seed production and generally tree shakers are used. In tropical area harvesting is done with climbing crews. (People) Seed Orchards: Seed orchard is a plantation of selected clones or progenies which is isolated and managed to reduce pollination from outside sources and managed to produce frequent, abundant and easily harvested seed crops. Objective of Seed orchard: The basic of assumption of establishing seed orchard is that there will be exchange of gamets among selected superior parents only. Because of isolation and in the process the resulted progeny will yield good genetic gains. Objectives: 1. To get genetically superior progenies in abundant quantities year after year. 2. In case of bio clonal orchards, production of hybrid seeds is also achieved. 3. In case of seedling seed orchards establishment of seed orchard genetic testing of parent can also be done. 4. Many a times seed orchards act as repositories of elite clonal material. Types of Seed orchards 1. clonal seed orchard 2. Seedling seed orchard 3. Evolving seed orchard

Clonal seed orchard 1. Type of planting material used for Establishment of clonal origin (vegetative propagated) 2. Genetic similarity with planting material (ortet) 100% Similar due to veg.prop 3. Genetic diversity of orchard depends on number of clones used however always lesser than seedling seed orchard. 4.Magnitude of genetic gain obtained will be larger in C.S.O 5. Opportunity for inbreeding is more because a genotype occurs more than once in C.S.O 6. Time of first flowering much shorter 7. Combining establishment of orchard and genetic testing of the parentsNot possible, a separate and concurrent genetic testing of parent need to be undertaken 8. Problems with the conversion of progeny test plot into a seedling seed orchard seedling seed orchard seed materialGenet 50% similar because of open pollination in the wild Larger than C.S.O Less than C.S.O Inbreeding possibilities are minimum because of the seed origin of planting material Period is larger It is possible to club both provided orchard establishment is done in isolation and suitable designs are adopted 1. Establishment of progeny testing plot should be undertaken in an area which is more suitable for flower and fruit production. 2. Following genetic rouging large space occur and hence uniform spacing is not maintained. 3. Since commercial spacing is adopted while establishing progeny test plot, silviculture thinning of plots is necessary to increase spacing between individual trees in order to encourage profuse flowering. 3. Evolving seed orchard: These are essentially seed orchard upgraded with newly identified clones in those places where previous clones have been genetically rouged because of their poor performance in progeny testing. In ESO, comparison of clones keeps changing as and when genetic test data is obtained and newer plus tree are identified. 4. Bioclonal hybrid seed orchard As name suggests, CSO consist of two most superior clones grown to encourage random mating between the clones to get desirable hybrid seeds. Since most of the tree species are self incompatible. Seeds collected from either of the parents is a truly hybrid seed. While selecting the clones for hybrid seed orchard testing for their high specific combining ability (SCA) is must.

Seed Orchard generations: I-generation seed orchard usually results from selection of superior individual from natural stands or unimproved plantation adopting of parent trees are not known. II-generation S.O are advanced generation seed orchard is established from obtaining planting material from I-generation S.O based progeny test data. Genetic gain obtained from II-generation S.O is much larger than first. Some scientist erroneously refer to 1.5 generation orchard to designate a clonal seed orchard which has been genetically rouged, essentially they are highly improved first generation seed orchard. Seed orchard location: It is crucial to have an ideal location for the establishment of seed orchard considering following 1. Climate should be congenial for insect activity during flowering. Most of commercial trees like teak flowers during rainy season. 2. Topography : location should be flat and easily accessible and minimizing soil work 3. Soils: Soils with good drainage, medium depth and moderate levels of nutrition are highly preferred since they encourage profuse flowering. Highly fertile soils often delay the onset of first flowering. 4. Water supply should not be a problem in the location 5. Areas with known pest and disease hot spot should not be selected. 6. Pollen dilution zone and isolation distance. The orchard must be located in a location which is completely free from outside pollen grain. A dilution zone of 150 m for Pines and 500m for Teak should be maintained. 7. Location should be such that, there not be destructive animal problem material and availability of labour should be good. Seed orchard Size: Ideally seed orchard size depends on the demand for quality planting material and seed set percent and seed size of the species availability of land. 2ha -------minimum size----Pine 23ha-----Eucalyptus 20ha------Teak Seed orchard management: Seed orchard management is a complex protocol varies with respect to species, location of orchard, condition encountered in a year. Broad thumb rules are given below. 1. Seed management: Soil texture management to increase drainage, nutrient availability and reduce root parasites is a must. During early stages of seed orchard development measures to increase soil fertility by growing soil enriching plant. Ex. Velvet bean 2. Seed Orchard fertilization: Based upon soil analysis, foliar application or soil amendments are to maintain plant vigour and to promote flowering. Application of nitrogen and phosphorous has promoted flowering and fruit set in many heartwood species. Maintaining optimum soil pH by application of lime is one of the most important aspect to increase nutrient availability.

3. Irrigation: To protect and to promote early growth is must. Once the orchard reaches flowering stage moisture conservation measures could be taken up. 4. Pest problem: Eradicating pest from seed orchard is a must. To obtain economically feasible seed crop control of orchard pest is a must. Seed Orchard Management: Main objective of seed orchard is to produce abundant quantity of seeds. Improvement in the genetic quality of seed crop is ensured only when there is random pollination among clones specific seed orchard designs are adopted. Seed Orchard Design: Is layout of allocation of every ramet of clone in a orchard designs are complicated and generated through computer such that no two ramets of the same clone are planted side by side. There are more than 200 designs are available based on number of clones used in a orchard. The simplest is randomized block design in which number of ramets per clone and total number of clones are equal. Ex. If 24 clones are used they will be replicated in 24 times and every row is a block. Ramets of diff clones - - - - 24 25 Block The only condition laid out while planting is that the ramets of same clone should not be the neighbor. 2. Completely randomized Design 3. Moving Circle design 1 2 3 4 Is a computer generated design with no block but it ensure that neighbouring ramets are always from two different clones Management Practice that increase flowering: 1. Spacing Teak-------5-6 mt between ramets and rows

2. Bole management Topping to get more flowers. In a seed orchard trees are managed to increase their flowering branches, canopy depth such that good amount seeds can be collected per individual. For this even though the clones are derived from superior phenotypes of clean bole ramets in an orchard often looks acquard with respect to bole structure. 3. Fertilization: N/P 4. Creating Stress Creating abiotic stress such as drought during flowering induction period increases intensity of flowering. 5. Growth regulators Foliar spray of GA2/7, paclobutrozol it is xylem compatible floweriegen. Micronutrientsalso induce. 6. Girdling Partial girdling of flowering branches can be practiced to increase flowering. Ex. Pine 7. Soil Working around tree Partial disturbance of a root system increases growth regulator concentration endogenously there by increasing flowering. Seed Orchard Records: Seed orchard record provide a history of all the management practices Such as they identify genetic material, graft compatibility, etc. which are of high importance in genetic up gradation of orchards. Two types of records are maintained. I. Those related to orchard as a unit such as a. Irrigation and fertilizationFrequency of irrigation, kinds of fertilization, date of fertilization. b. Sub soiling work c. Protective sprays for insect and disease control d. Date and type of pruning e. Rouging and thinning f. General condition of orchard with respect to weather condition, frost, drought heavy rain etc. g. Incidence of wild animals II. Those related individual clones and trees. a. Method and date of propagation b. Degree of graft compatibility c. Flowering- Time of first flower - Intensity of flowering - Date of pollen shed and female respectivity. d. Fruit production and germinability - Amount of seeds production Date of seed production e. Susceptibility to pest and diseases f. Special instruction for individual handling of ramets.

Research Seed Orchard/ Clone bank. A research seed orchard or a clonal bank is established to generate academic information on important clones with respect to their resistance characters, drought tolerance, wood quality parameters etc. a small number of clones 10-15 clones are maintained by planting 5-6 ramets each at a closer spacing to facilitate handing of flowers etc. experiment hybridization is also followed. They form important set of germ plasm for further breeding purpose. Contained Seed Orchard Are practiced in temperate countries where all the ramets of all clone are grown in large pots and maintain under controlled condition of green house. Every ramet clone can be moved to any position to facilitate artificial hybridization. Commercial important such as Nutmeg which is dioecious in nature are employed in containerized seed orchard. Hybrids in Forest trees: Hybrid: is offspring of crossing between genetically dissimilar parents of the same genus. In case of forest tree species, the term hybrid is referred to the product of a cross between two related species. In forestry, a hybrid is always an interspecific hybrid ex., hybrid of 1. Acacia mangium X Acacia auriculiformis Fast, heart rot crooked, resistance 2. Pinus coulteri X Pinus jeffereyi Slow, resistant to weevil fast, susceptible 3. Loblolly pine X long leaf pine 4. Eucalyptus spp. In case of forestry hybrids have been exploited to combine desirable characteristics of two related species into one offspring. ex., Acacia mangium X Acacia auriculiformis heart wood resistance is combined with good girth. PineResistance to pine weevil is combined with better growth. Loblolly pine Resistance fusiform rust long leaf---faster Development of artificial hybrids is tedious and time consuming effort. It is rather hit-or-mis approach. When hybridization is done between two parent a great variability is produced among offspring it is upto the tree breeder to select the desirable combination of characteristics. Further even if a desirable hybrid is identified mass multiplication of that individuals to develop planting stocks for operational level programmes is difficult. For this reason hybrids in forestry are mostly restricted to natural hybrids. Hybrid Vigourhetrosis Generally hybrid vogour refers to superiority of the hybrid over its parents. However not always the vigour of the F1 hybrid may not be than the parents. Natural Hybrids in Forest tree species. Prerequisites for natural hybridization 1. Existence of related species of a genus which show relative degree of compatibility 2. Intergrading ( over lapping of geographical distribution) of one population with other 3. Overlap of flowering phenology of species 4. Survival and adaptation of natural hybrids

5. introgression of introgressive hybridization is defined as limited spread of genetic material from one species into another as a result of hybridization followed by replicated back crossing of the hybrid and its progeny to one or both the parents. Introgression has been used as one of the technique artificially develop hybrid. Making artificial hybrid is not easy. Use of special techniques such as embryo rescue technique is adopted where in fully developed embryo is existed from a flower whish is pollinated with pollengrains of related species. This embryo is then grown under as artificial medium. It is followed in case of 1. Pinus lamberstiana X Pinus armandii 2. Supplemental mass pollination (SMP)(Hyun) In Cariya control pollination between Pinus talda X Pinus rigida have been done on a mass to develop artificial interspecific hybrid (Hyun) Both hand pollination and SMP are adopted to produce a hybrid Long leaf Pine and Loblolly Pines are also produced using SMP. 3. A method has been successfully developed to produce hybrid Eucalyptus in Florida and in Brazil which consist of establishing a orchard of one species within which individuals of another species are planted and from which hybrid seeds are collected. Following the development of a hybrid mass production of planting stocks has to be produced using vegetative propagation or tissue culture. Only in case of Pine and Eucalyptus hybrid seeds have been used just like F1 hybrids of agricultural crops. There is no universally accepted nomenclature for hybrids in forestry. Since the hybrids have general both the parents it is necessary to represent the species name of the parent. There are 3 broad norms for naming hybrid. 1. Use of a collective name with the sign X Ex. Pinus X rigida. 2. Using the names of both the parents. Such asPinus rigida X Pinus radiate The names are alphabetically organized in such a way that the female parent should come first. 3. Name of the cultivar (hybrid) begins with a capital latter along with nomenclature followed in to Ex. Pinus (rigida X radiate )= P Cv rigida Why hybrid production is restricted? 1. Inability to produce mass produce through seeds 2. Lack of suitable methods to produce hybrids vegetatively on mass scale 3. Inability to carry on F1 generation to F2 as in the case of field crop species.

Wood and Tree Improvement: Wood is a biological tissue made of cells (trachieds) that are composed of lignified cell wall. Quality of wood is highly linked to the utility or the purpose to which wood is put into. Based on usage number of quality parameters can be derived. However wood density or wood specific gravity is the most important property that influences the wood quality in nearly all products. Wood density/ Sp. Gravity Specific gravity = Weight of a given volume of wood Weight of an equal volume of water Density = Weight of the wood per unit of volume. In metric system Kg/m4 In metric system Density = Specific gravity 1000 Specific gravity of wood Influenced by. 1. Cell Size: The specific gravity of wood increases with number of cells per unit area. Smaller the cell size more number of cells can accommodate. 2. Cell wall thickness: Larger the cell wall higher will be the density because of higher cellulose content in the cell wall. 3. Amount of summer wood: The amount of summer wood which is also called as late wood contributes density of wood because of their thick cell wall. Hence overall sp. Gravity of wood will be higher if percentage of summer wood is larger. The amount of summer wood produced varies in species. Between provenances of species, in some extent between individuals of a population. Wood specific gravity, tree wood quality parameter since it influences the yield and quality of product as well as it is strongly inherited. Juvenile wood vs. mature wood It has been long recognized that wood properties within an individual. Generally speaking density of wood from upper canopy will be much lesser compared to the density of wood from tree bottom. This is because of variation of amount in juvenile wood and matured wood. Essentially juvenile wood formed when the tree was in juvenile stage and hence it is nearer to the pith. The mature wood on the other hand is formed when tree becomes older. The following properties of juvenile wood influence the wood quality. 1) Juvenile wood has lower specific gravity than matured wood. 2) The trachieds of juvenile wood are shorter. 3) The juvenile wood is unstable when dried and shrinks longitudinally. 4) Juvenile wood is weak compared to matured wood. 5) Because of within tree variations in specific gravity of wood it is very essential to sample wood from the same height of all individuals to be compared.

Genetic improvement of wood specific gravity 1) Use of variations in specific gravity across geographic area or provenance selection. Wood specific gravity is highly heritable and highly influenced by provenance features. Selection of the right provenance would result in almost 100% genetic improvement. E.g. in Pines, provenances in northern latitudes have lower density and shorter tracheids than southern latitudes in America. Further in land provenances have lower specific gravity than coastal ones. 2) Between individual, variation within a provenance is lower and hence, individual selection may not be important. 3) Since the trait shows high within individual variation. Sampling should be done at a constant tree height. 4) Whenever a tree leans a kind of different wood is formed to strengthen the tree. These woods are collectively known as reaction wood. The amounts of reaction wood in individual largely over estimate the density and influence the uniformity of wood. Further knots associated with branching pattern and canopy is also influenced by tree form. For this reason genetic improvement of tree form can lead to more uniform wood specific gravity. Forest Genetic Resources: Resource is a commodity that can be used for welfare of human society. Genetic resource is a living organism that has either current or potential use because of its specific genetic traits. Germ Plasm: Is a material harboring genes for present or future use. Principles of conservation and utilization Following are the principle steps in conservation and utilization of forest genetic resource. A forest genetic resource manager is generally involved in following activities. 1. Exploration of genetic resource. 2. Collection of genetic resource for evaluation. 3. Evaluation of genetic resources. 4. Conservation of genetic resource. 5. Utilization of genetic resources. For practical purpose field activities associated with exploration can be divided into 1. Botanical exploration 2. Geneocological exploration 1. Botanical exploration includes correct taxonomic identification of species, knowledge about its geological distribution specially with respect to isolated population, phonological information and regarding actual collection. In gene ecological exploration the entire range of phenotypic variation of a species are studied pilot basis and a sampling strategy is prepared to make further collection. 2. In this step small amounts of germplasm are collected from relatively large number resources covering the entire natural range of species. In other words, range wide collection of germplasm is made. Collections are made from natural population as well as introduced material. 50-75 distinct locations have to be covered and in each location seed samples of 30 individuals have to be collected. 3. Evaluation:

establishment of provenance trail aimed at revealing potential useful variability, degree to which a genotype can adopt to itself and economic value of provenance. Every step in the provenance trail needs to be followed strictly. 4. Conservation: Conservation in its practical sence includes preservation and utilization of genetic resources. Conservation of forest genetic resource is an aspect of rfesource management which ensure the utilization of resource is sustainable at the same time safeguarding the genetic diversity essential for the maintenance. Main strategies of conservation are as follows 1. Conserving ecosystems by carefully selecting the areas of adequate size with suitable management policies. That would conserve the all elements of ecosystem. 2. Conservation of rare and threatened species that require urgent attention. This strategy automatically incorporated in the first strategy. 3. prevention of genetic erosion or prevention of depleting genetic variability. Two methods of conservation: 1. In-situ Conservation Conservation of species or a provenance as a part of viable, exotic ecosystem. This is most desirable form of conservation method. In practice conservation of forest tree genetic resources in-situ, are combined with other elements of eco system such as charismatic animals. All protected areassanctuaries, national parks, tiger reserves, ecologically sensitive area, conservation reserves, community reserves, natural heritage sites, biosphere reserves. 2. Ex-Situ Conservation Although in-situ conservation is more ideal, there are instances where in-situ protection is not possible for all the species because of technical, biological, political or social difficulties. Ex-situ conservation is especially useful when dealing with certain species that are amenable for this approach. Ex-situ conservation methods may include the following. a. Seed Orchard b. Clonal banks c. Conservation stand d. Storage of seed and other reproductive material. e. Storage of DNA. Under ex-situ conservation stand, three types exist 1. Static conservation stand- where original natural stand is duplicated. 2. Evolutionary conservation stand - in which natural selection is allowed to operate. 3. Selective conservation stand- where gene frequency in stand are deliberately changed to recover economically important traits. 5. Utilization: It is the ultimate objective of all activities concerned with forest genetic resources. It comprises of use of genetic resources to breed better adopted and economically desirable genotypes. Every step of tree improvement programs comprises this activity.

Breeding for Insect Pest and Diseases One of the important objectives in tree improvement is to reduce, manage by decease and insect pest and to produce genotypes that are particularly suited to grow under adverse environment. In general following three terms are used to describe levels of resistance to pest or decease. 1. Immunity- refers to total lack of any symptom or damage due to the pest. Very rarely immunity is expressed in forest tree species. 2. Tolerance refers to degree to which a tree can grow with a pest or decease symptom and still retain its economic value. 3. Resistanceis a specific term that refers to ability of a specific genotype of the host to tolerate a specific race of the pest. However, resistance and tolerance are interchangeably used. While breeding for decease resistance, the following two terms are used. 1. Horizontal Resistance 2. Vertical Resistance. Vertical resistance refers to complete resistance of a specific clone to a few of the disease causing organism or pathogen (clones showing vertical resistance to certain pathogen are susceptible to other pathogen Horizontal Resistance. In this type, host genotypes are moderately resistant to a broad range of pathogen races. The term horizontal and vertical resistance have been coined based on the graphical illustration for these two types of resistance. The objective of breeding for pest resistance is to reduce the damage to a tolerable level. Breeding for pest resistance is important for following reasons. 1. Once a genotype with specific resistance is obtained it can be used for a long commercial cultivation without breaking down of resistance (resistance is relatively permanent) 2. Controlling a decease or a pest through management is often expensive and environmentally unfriendly.

There is no simple answer about how to proceed in a breeding program against pest. The knowledge of the following is necessary while constructing a breeding program 1. Economic worth of a host. 2. Potential economic loss from pest. 3. Biology and genetic variation within a host species. 4. Biology and genetic variation of a pest. 5. Interaction of an environment with tolerance of host virulence of pest. 6. Interaction between the pest and the host. Special features of Selection- pest resistance and disease 1. The selection must be done in heavily infested stand whenever mass selection is undertaken. This reduces the chance of escape of trees i.e. a non resistant tree passing the test. 2. Susceptibility to the pest is highly depended character on the age of the host. It is always necessary to specify the correct age of plantations for selection. 3. Whenever genetic tests are conducted (such as progeny test and provenance test) all trees must be subjected to at least moderate levels of pest attack. Breeding methods for Disease resistance: 1. Family selection-Much success has been obtained by adopting family selection in temperate species. Resistance to phytopthora in Pines, resistance to fusiform rust in pines, resistance to leaf rust in sweet gum have been obtained by family selection. 2. For rust and canker diseases individual selection in wild populations has been successful. 3. Developing of hybrids through inter specific crosses has been successful. Ex. Short leaf pine X loblolly pine However in chestnut little improvement is achieved through hybridization. 4. Selection in the laboratory through forced attack or through creating artificial pest and disease condition What are the mechanisms of resistance to diseases? 1. Exclusions: Certain host genotypes escape the attack by disease or pathogen merely because of phonological events such as early leaf flushing not coinciding with high humidity. Late flowering or late fruit set etc. this is not a true resistance feature exclusion reduce or minimize the economic loss. 2. Walling off: - Restriction of the growth and spread of pathogen by different mechanism after pathogen has gained entry. This is an active resistance mechanism. 3. destruction of the pathogen after the entry into the system: -secondary metabolites such as terpene, phenols have been shown to reduce the growth of pathogen inside the plant system. Breeding for insect pest Reasons for less progress in insect resistance in forest trees. 1. mobility of the insects.- manipulation of the insect is extremely difficult. 2. Lack of ability to predict where and when an insect attack will occr.

3. Lack of knowledge of insect genetics. 4. Lack of knowledge about what causes insect resistance. 5. Difficulty in creating artificial infestations under controlled conditions. Resistance mechanism for insect pest: 1. Non- preference Is nothing but the insect pest not attacked to the host even if it is attracted it is repelled from feeding and oviposition. 2. Antibiosis Life cycle after feeding 3. Tolerance - A tree recovers from insect attack after certain period and produces normaly. Methods for breeding pest Resistance: 1. Selection of geographic races and individual families against the pests. Ex. Resistance to white Pine weevil through selection geographic races. 2. Resistance on an individual tree basis is the most important control of tree damage. Ex. Selection of black Pine against Pine gall midge. Selection of teak clones against teak trunk borer. Clones with higher bark thickness are resistant. Since young larvae can not bore into the heartwood. Genetic variation, Heritability and Combining Abilities: Variation in tree population can be partitioned into genetic and environmental components hence the basic model of variation is Phenotypic value= genotypic value+ Environmental value P=G+E The same model can be extended as follows Phenotypic variation= Genotypic variation + Environmental variation Which can be written symbolically as. VP=VG+VE Genetic values are influenced by both additive and non-additive effects. Additive effects are those due to additive effect of the genes hence they are fixable in a population. Additive effects are due to general combining ability (GCA). Non-additive components are heritable but not fixable in a population. Nonadditve effects are due to, specific combining ability (SCA). Thus the model for phenotypic variation can be written as VP=[ VA+VNA] + VE Heritability: The concept of heritability is most important and most used in quantitative genetics. Heritability value express the proportion of variation in the population i.e. attributable to genetic differences. It is expressed as the following ratio. H2= VG/VP x 100= Broad sense heritability. The value of H2 vary from 0-100 when expressed as percentage. However it varies from 0-1 Narrow sense heritability is the ratio of additive genetic variance to the total phenotype variance. h2 = VA/VP x 100 where, Va= variation due to additive genetic component. = Narrow sense heritability.

The value browd sense heritability is always higher than narrow sense heritability. For tree improvement programme narrow sense heritability are considered than broad sense heritability. Features of heritability: Heritability is conceptual issue and they are estimated by statistical tools. Values of heritability are only suggesting the relative strength of the genotype influence. Heritability values are character specific. For instance, wood specific gravity is more heritable than heritable for height. (Wood Specific gravity varies from 0.550.80 & 0.1-0.3) General Combining Ability (GCA) It is defined as average performance of progeny of an individual mother tree when it is mated with number of individuals in a population. Higher the GCA for the parent better is it to be included in a seed orchard. Specific Combining Ability (SCA) refers to average performance of a progeny of a cross between two parents. SCA is utilized to select the trees for hybrid production because they have higher VNA component. Biotechnologies and their application in forest tree improvement Biotechnology is not a science; it is a bunch of techniques and tools used to take the target organism for the benefit of human society. Scientific basis of modern biotechnological tools is studied under molecular technology. Molecular biology provides scientific basis and understanding necessary for genetic tailoring of organisms. Important technologies relevant to tree improvement. 1. Micropropagation 2. Somaclonal Variation 3. Protoplast fusion 4. Gametophyte cultures 5. In-vitro Selection 6. In-vitro embryo rescue 7. Molecular markers 8. Genetic engineering 9. Cryo-preservation and in-vitro storage 1. Micro-propagation (tissue Culture) is a generic term that includes in-vitro growth and population of relatively unorganized cells( cell culture), of callus (callus culture), of particular tissues such as roots and shoots(organ culture). In forestry most organ culture is commonly used to propagate forest tree species.

Major advantages of Tissue Culture. 1. Rapid and exponential proliferation of materials to produce plantlets of desired types. 2. Ability to store small number of cultures from every clone under dormant condition while clones are being tested and rapidly multiplying these clones after selection. 3. Well standardized protocols for micro-propagation is necessary before any genetic engineering techniques are adopted. Micro-propagation protocols have been established for >1000 plant species under which only hundred are of forestry importance. For a large number of tropical broad leaved species, the protocols are not yet available. It concluded that the research efforts are necessary to standardize micro-propagation protocols of economically important tree species. e. g. SPECIES PLACE Tectona grandis NCL, Pune. Santalum album Indian Institute of Sciences, Bangalore. Tamarindus indica NCL, Pune Dalbergia sissoo Delhi University Dalbergia latifolia NCL, Pune Eucalyptus tereticormis Regional Research Centre, Jammu Heavea brasilensis NCL Pune. Bamnusa arundinaceae Delhi university Albizia lebbeck Delhi university Pinus wallichiana NCL Pune 2. Somaclonal variation Variation induced during cells/callus culture has been reported in several species. Some of the economically important trades such as salt tolerance, Resistance to disease and pests have also been reported in some species. Use of somaclonal variation is very important while selecting in vitro at the cellular level. Ex. Tolerance to cold has been selected in Eucalyptus. Screening for resistance to high phytotoxin levels is under the spruce. There is no immediate applicability of this technique to the known tropical hardwood and non-industrial species because the total genetic variability available for many species is not known and standardized protocols of micro propagation are not available. 3. In vitro selection In vitro selection can be made at different levels such as whole parents, pollen grains, embryos, and cells. In general In vitro selection involves selection of cells or protoplasts using an artificial induction of stress. The following are the in vitro selection for a. Disease resistance, herbicide tolerance, salt tolerance, tolerance for heavy metals, tolerance for water stress, tolerance for high and low temperature, for a successful in vitro selection system following criteria are necessary. 1. Presence of a correlated trait i.e. correlation between performance of adults and performance in vitro 2. measurement of both the traits should be easy. The variability within target and selection trait should be easy. 3. heritability of both characters should be high

Application in forest tree improvement 1. Cold tolerance is an important selection criteria in tree species such as Eucalyptus when ever it is introduced to temperate area. 2. tolerance to salt and metals is important in a large scale rehabilitation in wastelands, salt affected areas and mined areas. 3. herbicide resistance is an important trait in forest tree species that are introduced as tree component under agro-forestry system. 4. large scale mechanized plantation. 5. in vitro selection for cold tolerance is successful in E. gunnii. Application of forest tree genetic engineering 1. There are two strategies for improving the forest tree species using genetic engineering. Transforming the existing genotypes with novel genes that impart special qualities such as herbicide tolerance, insect tolerance, cold tolerance etc. 2. Transforming existing genotypes with genes leading to blocking of protein synthesis. Ex. Reducing the production of unwanted metabolites, metabolise that are responsible for pollen production. Production of male sterile lines is an important area of research using this approach. Target trait that are important for gene manipulation. 1. Insect resistance 2. bacterial & fungal resistance 3. virus resistance 4. nematode resistance crises that are important-B.T gene/ protienase inhibitive 1. Herbiside tolerance 2. Cold tolerance ImpgenesDetoxifying gene, Antifreezing gene. 3. Wood Properties Reduction in lignin through enzyme regulation. Modification of lignin production. In case of pines, 3 enzymes have been characterized that reduce the lignin production. 4. Male sterility-Has been indused in Poplar, Eucalyptus, Pinus spp, by modifuing genes responisible for another bursting. Molecular markers: In general two kinds of molecular markers are used. 1. Molecular genetic markers 2. Biochemical markers Molecular genetic markers are derived from the analysis of polymorphic DNA sequences. The biochemical markers are derived from biochemical products in a plant system such as proteins. Ex. Molecular genetic markers RAPD- Randomly amplified polymorphic DNA RFLF - Restriction fragment length polymorphism Microsatellites= SSR Simple sequence repetes. Biochemical markers Isozymes.

Application of molecular marker in tree improvement: 1. Assessment of genetic diversity for conservation purpose. 2. Verification of genotype and delineation of genotype 1. Delineation of genotypes: New release of verities and separation of genotypes which are of controversy can be done using molecular markers. Genetic finger printing of clones in a seed orchard rouging of mistypes maintenance of genuinity etc can be done. 2. Application in taxonomy and phytogenetics studies. Molecular markers can be used in understanding the phytogenetic relationship between two related species or genera. It can also be applied to naming an Interspecific hybrid. 3. Market assisted selection (MAS) QTLQuantitative trait loci. Marker assisted selection involve recognition of strong association between a set of loci called QTL=qualitative trait loci and economically important trait such as yield, resistance to pest and disease tolerance to abiotic stresses etc, QTL s have been developed for Pinus lambertiana to select a resistance to disease. MAS has been applied to selection of lines with higher pest resistance in Pinus hybrid. Cryopreservation and invitro storage: Application in T.P 1. Germplasm preservation Transport of germplasm, maintenance of juvenility, preservation, pollen quality, seed storage etc. Ex. Trough cryo preservation, embryos of follwing species have been preserved includesArtocarpus. Quercus, Fagus,. Embryonic cell lines have been preserved of Picea alba, Pinus taida, seeds are preserved of Pinus silvastris, pollens of Betula pendula. In case of, Eucalyptus gunnii encapsulated shhot tips are preserved.

Cornell's Sugar Maple Tree Improvement Program The amount of sugar in maple tree sap is variable. Some trees, especially those grown in the open, may have high sap sugar concentrations, ranging from 3 to 4%. There are also differences in sap sugar concentration from year to year. One year, a tree might have 2% sugar and the next year 3%. What factors might influence sap sweetness? Why are these differences in sap sugar concentration so important? The answer is simple: the higher the sugar concentration, the less water needs to be boiled off to produce syrup (~66-67% sugar), and the less the producer will need to pay for the fuel used in the boiling process. Knowing that trees grown in the open generally have higher sugar concentrations would help maple producers decide which trees to tap, or even where to plant young trees. But

what about all the trees growing in the forest? Is there any way we can increase their sugar content? For many years, maple scientists and farmers wondered if there might be genes that controlled sugar content in maple trees. If youve had biology in school, or simply observed family and friends, you know that tall parents are more likely to have children who grow to be tall. But is a maple tree with high sugar content more likely to produce seeds that will grow into new trees with high sugar content? Or are environmental variables, things like whether a tree is grown in the open or yearly variations in the weather, the only thing that controls sugar content of sap? Starting in the late 1950s, maple scientists began to search for an answer to this question: Can high sugar content be inherited from a parent tree? Before you read the next section that describes how the scientists tried to answer this question, you might want to imagine you are a scientist investigating this question. How would you go about finding out if parent trees pass on a trait for high sap sugar to their offspring? Field Examination and Selection The first thing the maple scientists did was find trees that had high sugar content. Scientists from the US Forest Service worked with county foresters to test 21,000 trees from throughout the Northeast. They measured the sugar content of sap from each tree using hydrometers and refractometers (click here for details on these instruments). Many of the trees they tapped were identified by maple producers, who knew from years of working their sugar bushes which trees were "sweeter" than others. You might also want to measure sugar content in sap of maple trees in your area, and perhaps help find sweet trees that could become part of the Sugar Maple Tree Improvement Program. Click here for details.

Screening to Select the Very Best Trees Of the 21,000 original trees tapped, the scientists identified 53 trees that they felt had promise for the tree improvement program. These trees had higher sap sugar content than their immediate neighbors and were healthy and free of any defects. Clonal Bank Do you remember "Dolly," the cloned sheep? Foresters have been cloning trees for years. This allows them to produce trees that are genetically identical to the parent tree. Trees are also produced by seeds. Seeds have a portion of their genetic material from pollen, which may come from a different tree than the tree producing the female flowers and seeds. Thus, trees grown from seed have only half of their genetic material from the mother tree. In the Sugar Maple Tree Improvement Program, scientists knew that the sugar content of sap was influenced by the environment. They wanted to determine whether the genetics of the tree also influences sugar content of sap. If the scientists had used seeds from the 53 original trees, the pollen would likely have come from a tree with lower sugar content than a tree selected for the Sugar Maple Tree Improvement Program. Thus, trees produced from seeds would have been less likely than trees that were cloned from the original trees to have high sap sugar content, if sap sugar content is genetically controlled. Therefore, the scientists wanted to test trees that were genetically identical (clones) of the original 53 "sweet" trees. But how do you get clones of trees? The first step in cloning a tree is taking a "cutting" or branch of the parent tree. The cuttings can then be "grafted" or allowed to grow onto roots ("root stock") of an existing tree. If you are familiar with grafting apple trees, you know that any genetic characteristics of the apple tree cutting will be expressed above the point where the cutting is grafted onto the rootstock. For example, if you take a cutting from an apple tree with crisp, green apples, and graft it onto rootstock from a tree with mushy, red apples, the new tree will produce crisp, green apples above the point where it is grafted. This same principle would hold for maple trees. If sap sweetness is genetically controlled, then a grafted tree should have similar sap sweetness to the parent cutting above the point where the tree is grafted. Alternatively, cuttings can be "rooted." This involves treating the cuttings with hormones under special greenhouse conditions so that the cuttings form their own roots. It can be a tricky business as it involves growing the cuttings under just the right temperature, moisture, light, and nutrient conditions. Scientists from the U.S. Forest Service and Cornell University have pioneered new methods of developing roots on sugar maple cuttings.

Another advantage of using cuttings rather than seeds has to do with how fast the next generation of seeds is produced. Whereas a tree produced from a seed takes more than 20 years to produce its own seeds, a tree produced by grafting or rooting cuttings can produce seeds in just three or four years. In 1968, the cuttings from the trees selected for the Maple Tree Improvement Program were grafted onto root stock in Grand Isle, VT, at a site owned by the US Forest Service. In 1983, a second group of cuttings were grafted onto root stock or "rooted" in the greenhouse and planted at Cornells Uihlein Sugar Maple Field Station in Lake Placid, NY. These two plantings of the 53 original trees are called clonal banks. Their purpose is to provide seeds and cuttings to grow more "sweet" trees. Every year researchers at the Uihlein Station plant seeds of adult clonal bank trees in small pots. These seeds grow into saplings in the greenhouse during the spring and summer, and are stored in the underground storage bunker during the winter (funding for the bunker was provided by the New York State Maple Producers Association). The cycle is repeated until they have completed two full winters; at this point they are available for outplanting. Contact, Uihlein Station Director, for more information. The clonal banks thus represent years of work involving examining over 20,000 trees and research to determine how to propagate them. They are valuable genetic resources that we need to maintain for the future. Progeny Tests When they established the clonal banks, the scientists didnt actually know whether trees grown from seeds of the cuttings would have high sap sugar content. Can you figure out a reason why they couldnt be sure?

Maybe the 53 trees selected for the clonal bank all happened to be growing in a slightly different environment than other trees nearby. For example, there could be slightly more light or higher nutrients in the soil. If sugar content were only controlled by factors in the environment, then the trees produced from cuttings, growing in a different environment, would not be expected to have high sugar content. To determine whether sap sweetness is genetically controlled, the scientists established "progeny tests" using seeds from the clonal bank in Vermont. The progeny tests were established in 1983 at two sites: the Uihlein Sugar Maple Field Station in Lake Placid, NY, and on private land in West Salisbury, PA. A progeny test is an experiment in which seeds are taken from a number of different trees that were originally growing in different environments. The seeds are planted at a site that has a uniform environment. The differences between the trees are then measured. Because the environment in which the plants are grown is constant, any differences between the trees in a progeny test are genetic. The trees in the sugar maple progeny tests were grown from the seeds of trees in the clonal banks. Because the trees in the clonal banks are isolated from other sugar maples, it was assumed that the pollen that fertilized the seeds came from sweet trees in the clonal bank. Once the progeny test trees were about seven years old, they were large enough to test for sap sweetness. The scientists measured their sap sugar content. They determined that sap sweetness was indeed partly controlled by genetics. (Remember, the scientists already knew that environmental factors, such as weather and light, also influence sap sweetness. Many characteristics of humans as well as trees are controlled both by the environment and genetics.) First Generation Seed Orchard Once the scientists knew that it was possible to breed trees with higher sap content, they set out to produce more trees from the original "sweet" trees. Scientists at the Cornell Uihlein Sugar Maple Field Station selected the best trees from the progeny test to plant in the Lake Placid seed orchard. Eventually this orchard will produce seed for growers throughout the Northeast. Establishing Maple Seedlings Most maple producers tap trees that reproduced naturally from seeds in the forest. In the future, maple producers may want to plant trees that have been bred for sap sweetness and other characteristics. Because many farmers in the Northeast have recently taken land out of farming, abandoned fields are abundant and could be used for sugar maple plantations. But not much is known about growing maple seedlings in open areas like abandoned fields. Thus, the next step in the Sugar Maple Tree Improvement Program was to test different ways to establish seedlings in abandoned agricultural fields. Currently, twelve farmers from New York State and Pennsylvania are conducting experiments in cooperation with the Maple Team of the Cornell Sugar Maple Program, to see how well maple seedlings grow in abandoned fields in different regions of these states. We are hopeful that in the not too distant future, a commercial or state nursery will grow sugar maple seedlings from the seeds of the best trees in the Uihlein seed orchard. Maple

producers will be able to buy the seedlings grown from the seed of trees with high sap sugar content, and plant them on their land. When this occurs, research conducted by universities, the federal government, and private landowners working together over the past 40 years will have benefited maple producers throughout the northeastern US. Growing Maple Seedlings in Fields Once the maple seedlings are taken from the nursery or greenhouse and planted in the field, they are exposed to many factors that could affect their survival. Therefore, another set of experiments is being conducted to test different means of protecting maple seedlings from deer and other animals that might browse on them. Included in this field experiment are also sev